We use Instagram to share photos of the beauty around us, the delicious meals we've eaten or created, and our personal highs. But it is a social network, and we also use it to share our feelings when we're sad, upset, or when we need some moral support. Today, Instagram made some subtle but important changes to its app. Now, if you see a friend post something that feels like a cry for help, you can do something about it — without being confrontational.